647665428 has 12 divisors (see below), whose sum is σ = 1511219360. Its totient is φ = 215888472.

The previous prime is 647665393. The next prime is 647665433. The reversal of 647665428 is 824566746.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26986048 + ... + 26986071.

Almost surely, 2^647665428 is an apocalyptic number.

It is an amenable number.

647665428 is an abundant number, since it is smaller than the sum of its proper divisors (863553932).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

647665428 is a wasteful number, since it uses less digits than its factorization.

647665428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53972126 (or 53972124 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 48.

The square root of 647665428 is about 25449.2716595191. The cubic root of 647665428 is about 865.2007855814.

The spelling of 647665428 in words is "six hundred forty-seven million, six hundred sixty-five thousand, four hundred twenty-eight".